When Naaman was asked to dip himself in the Jordan river, he wasn't mad because it was a dirty river, he wasn't even mad about the simple instruction. What really made him frustrated was that he had an expectation that wasn't met. Sometimes, maybe even subconsciously, we place expectations or timelines on Heavenly Father. And if/when they aren't met we get frustrated. But when we approach God in faith and approach our disappointments in faith we can learn and grow and gain a better understanding of who God is.